Early American electromechanical computer (1944)
Harvard Mark I
Closeup of input/output and control readers
|
Also known as
| IBM
Automatic Sequence Controlled Calculator (ASCC)
|
---|
Developer
| Howard Aiken
/
IBM
|
---|
Release date
| August 7, 1944
; 79 years ago
(
1944-08-07
)
|
---|
Power
| 5 hp (3.7 kW)
|
---|
Dimensions
| - 816 cu ft (23.1 m
3
):
- Width: 51 ft (16 m)
- Height: 8 ft (2.4 m)
- Depth: 2 ft (0.61 m)
|
---|
Mass
| 9,445 lb (4,284 kg)
|
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Successor
| Harvard Mark II
|
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The
Harvard Mark I
, or
IBM
Automatic Sequence Controlled Calculator
(
ASCC
), was one of the earliest general-purpose
electromechanical
computers
used in the war effort during the last part of
World War II
.
One of the first programs to run on the Mark I was initiated on 29 March 1944
by
John von Neumann
. At that time, von Neumann was working on the
Manhattan Project
, and needed to determine whether
implosion
was a viable choice to detonate the atomic bomb that would be used a year later. The Mark I also computed and printed mathematical tables, which had been the initial goal of British inventor
Charles Babbage
for his "
analytical engine
" in 1837.
According to
Edmund Berkeley
, the operators of the Mark I often called the machine “Bessy, the Bessel engine,” after
Bessel functions
.
[2]
The Mark I was disassembled in 1959; part of it was given to IBM, part went to the
Smithsonian Institution
, and part entered the
Harvard Collection of Historical Scientific Instruments
. For decades, Harvard's portion was on display in the lobby of the Aiken Computation Lab. About 1997, it was moved to the
Harvard Science Center
. In 2021, it was moved again, to the lobby of Harvard's new Science and Engineering Complex in
Allston, Massachusetts
.
[3]
Origins
[
edit
]
The original concept was presented to IBM by
Howard Aiken
in November 1937.
After a feasibility study by IBM engineers, the company chairman
Thomas Watson Sr.
personally approved the project and its funding in February 1939.
Howard Aiken had started to look for a company to design and build his calculator in early 1937. After two rejections,
[5]
he was shown a demonstration set that
Charles Babbage
’s son had given to Harvard University 70 years earlier. This led him to study Babbage and to add references to the
Analytical Engine
to his proposal; the resulting machine "brought Babbage’s principles of the Analytical Engine almost to full realization, while adding important new features."
[6]
The ASCC was developed and built by IBM at their
Endicott
plant and shipped to
Harvard
in February 1944. It began computations for the US Navy Bureau of Ships in May and was officially presented to the university on August 7, 1944.
[7]
Although not the
first working computer
, the machine was the first to automate the execution of complex calculations, making it a significant step forward for computing.
[8]
Design and construction
[
edit
]
The ASCC was built from
switches
,
relays
,
rotating shafts
, and
clutches
. It used 765,000
electromechanical
components and hundreds of miles of wire, comprising a volume of 816 cubic feet (23 m
3
) ? 51 feet (16 m) in length, 8 feet (2.4 m) in height, and 2 feet (0.61 m) deep. It weighed about 9,445 pounds (4.7 short tons; 4.3 t).
[9]
The basic calculating units had to be synchronized and powered mechanically, so they were operated by a 50-foot (15 m)
drive shaft
coupled to a 5 horsepower (3.7 kW) electric motor, which served as the main power source and
system clock
. From the IBM Archives:
The Automatic Sequence Controlled Calculator (Harvard Mark I) was the first operating machine that could execute long computations automatically. A project conceived by Harvard University’s Dr. Howard Aiken, the Mark I was built by IBM engineers in Endicott, N.Y. A steel frame 51 feet long and 8 feet high held the calculator, which consisted of an interlocking panel of small gears, counters, switches and control circuits, all only a few inches in depth. The ASCC used 500 miles (800 km) of wire with three million connections, 3,500 multipole relays with 35,000 contacts, 2,225 counters, 1,464 tenpole switches and tiers of 72 adding machines, each with 23 significant numbers. It was the industry’s largest electromechanical calculator.
[10]
The enclosure for the Mark I was designed by futuristic American
industrial designer
Norman Bel Geddes
at IBM's expense. Aiken was annoyed that the cost ($50,000 or more according to
Grace Hopper
) was not used to build additional computer equipment.
[11]
Operation
[
edit
]
The Mark I had 60 sets of 24 switches for manual data entry and could store 72 numbers, each 23 decimal digits long.
[12]
It could do 3 additions or subtractions in a second. A multiplication took 6 seconds, a division took 15.3 seconds, and a logarithm or a trigonometric function took over one minute.
The Mark I read its
instructions
from a 24-channel
punched paper tape
. It executed the current instruction and then read the next one. A separate tape could contain numbers for input, but the tape formats were not interchangeable. Instructions could not be executed from the storage registers. Because instructions were not stored in working memory, it is widely claimed that the Harvard Mark I was the origin of the
Harvard architecture
. However, this is disputed in
The Myth of the Harvard Architecture
published in the
IEEE Annals of History of Computing
,
[14]
which shows the term 'Harvard architecture' did not come into use until the 1970s (in the context of microcontrollers) and was only retrospectively applied to the Harvard machines, and that the term could only be applied to the
Mark III
and
IV
, not to the Mark I or
II
.
The main sequence mechanism was unidirectional. This meant that complex programs had to be physically lengthy. A program loop was accomplished by
loop unrolling
or by joining the end of the paper tape containing the program back to the beginning of the tape (literally creating a
loop
). At first,
conditional branching
in Mark I was performed manually. Later modifications in 1946 introduced automatic program branching (by
subroutine
call).
[15]
[16]
[17]
[18]
The first programmers of the Mark I were computing pioneers
Richard Milton Bloch
, Robert Campbell, and
Grace Hopper
.
[20]
There was also a small technical team whose assignment was to actually operate the machine; some had been IBM employees before being required to join the Navy to work on the machine.
[21]
This technical team was not informed of the overall purpose of their work while at Harvard.
-
Tape punch used to prepare programs
-
Program tape with visible
programming patches
-
Rotary switches used to enter program data constants
-
Sequence indicators and switches
-
Rear view of the computing section
Instruction format
[
edit
]
The 24 channels of the input tape were divided into three fields of eight channels. Each storage location, each set of switches, and the
registers
associated with the
input, output
, and
arithmetic units
were assigned a unique identifying index number. These numbers were represented in
binary
on the control tape. The first field was the binary index of the result of the operation, the second was the source
datum
for the operation and the third field was a
code
for the
operation
to be performed.
[12]
Contribution to the Manhattan Project
[
edit
]
In 1928
L.J. Comrie
was the first to turn IBM "punched-card equipment to scientific use: computation of astronomical tables by the method of finite differences, as envisioned by Babbage 100 years earlier for his Difference Engine".
[22]
Very soon after, IBM started to modify its tabulators to facilitate this kind of computation. One of these tabulators, built in 1931, was The Columbia Difference Tabulator.
[23]
John von Neumann
had a team at Los Alamos that used "modified IBM punched-card machines"
[24]
to determine the effects of the implosion. In March 1944, he proposed to run certain problems regarding implosion of the Mark I, and in 1944 he arrived with two mathematicians to write a simulation program to study the implosion of the first
atomic bomb
.
The Los Alamos group completed its work in a much shorter time than the Cambridge group. However,
the punched-card machine operation computed values to six decimal places, whereas the Mark I computed values to eighteen decimal places
. Additionally, Mark I
integrated the partial differential equation at a much smaller interval size [or smaller mesh] and so...achieved far greater precision
.
[24]
"Von Neumann joined the
Manhattan Project
in 1943, working on the immense number of calculations needed to build the atomic bomb. He showed that the implosion design, which would later be used in the Trinity and Fat Man bombs, was likely faster and more efficient than the gun design."
[25]
Aiken and IBM
[
edit
]
Aiken published a press release announcing the Mark I listing himself as the sole “inventor”.
James W. Bryce
was the only IBM person mentioned, even though several IBM engineers including Clair Lake and Frank Hamilton had helped to build various elements. IBM chairman
Thomas J. Watson
was enraged, and only reluctantly attended the dedication ceremony on August 7, 1944.
[26]
[
page needed
]
[27]
Aiken, in turn, decided to build further machines without IBM's help, and the ASCC came to be generally known as the "Harvard Mark I". IBM went on to build its
Selective Sequence Electronic Calculator
(SSEC) to both test new technology and provide more publicity for the company's efforts.
[26]
[
page needed
]
Successors
[
edit
]
The Mark I was followed by the
Harvard Mark II
(1947 or 1948),
Mark III/ADEC
(September 1949), and
Harvard Mark IV
(1952) ? all the work of Aiken. The Mark II was an improvement over the Mark I, although it still was based on electromechanical
relays
. The Mark III used mostly
electronic components
?
vacuum tubes
and
crystal diodes
?but also included mechanical components: rotating
magnetic drums
for storage, plus relays for transferring data between drums. The Mark IV was all-electronic, replacing the remaining mechanical components with
magnetic core memory
. The Mark II and Mark III were delivered to the
US Navy
base at
Dahlgren, Virginia
. The Mark IV was built for the
US Air Force
, but it stayed at Harvard.
[
citation needed
]
The Mark I was disassembled in 1959, and portions of it went on display in the
Science Center
, as part of the
Harvard Collection of Historical Scientific Instruments
. It was relocated to the new
Science and Engineering Complex
in
Allston
in July 2021.
[28]
Other sections of the original machine had much earlier been transferred to IBM and the
Smithsonian Institution
.
[29]
See also
[
edit
]
References
[
edit
]
- Notes
- ^
Berkeley, Edmund Callis. Giant Brains, or, Machines That Think (Classics To Go) (p. 6). Otbebookpublishing. Kindle Edition.
- ^
Powell, Alvin (July 23, 2021).
"Harvard's Mark 1 finds its new home"
.
Harvard Gazette
. Retrieved
August 17,
2023
.
- ^
Cohen (2000)
, p. 39: It was first rejected by the
Monroe Calculator Company
and then by Harvard University.
- ^
"IBM's ASCC introduction 2"
. January 23, 2003
. Retrieved
December 14,
2013
.
- ^
"Proposed automatic calculating machine (Abstract)".
IEEE Spectrum
.
1
(8). IEEE Xplore: 62?69. August 1964.
doi
:
10.1109/MSPEC.1964.6500770
.
ISSN
0018-9235
.
S2CID
51652725
.
- ^
"The History of Harvard Mark 1: A Complete Guide"
. September 21, 2021.
- ^
"IBM Archives: Feeds, speeds and specifications ASCC Statistics"
.
www-03.ibm.com
. January 23, 2003.
- ^
IBM Archives: FAQ / Products and Services
- ^
"Grace Murray Hopper Interview"
(PDF)
. Computer Oral History Collection, 1969-1973, 1977. Archives Center, National Museum of American History. January 7, 1969. pp. 7?8. Archived from
the original
(PDF)
on February 23, 2012
. Retrieved
October 21,
2012
.
- ^
a
b
Maurice Vincent Wilkes
(1956).
Automatic Digital Computers
. New York: John Wiley & Sons. pp. 16?20.
- ^
Pawson, Richard (September 30, 2022).
"The Myth of the Harvard Architecture"
.
IEEE Annals of the History of Computing
.
44
(3): 59?69.
doi
:
10.1109/MAHC.2022.3175612
.
S2CID
252018052
.
- ^
Beyer, Kurt W. (2015).
Grace Hopper and the Invention of the Information Age
. BookBaby. pp. 78?79.
ISBN
9781483550497
.
- ^
Bloch, Richard (February 22, 1984).
Oral history interview with Richard M. Bloch
. pp. 9?10.
hdl
:
11299/107123
.
- ^
"The Erwin Tomash Library on the History of Computing: An Annotated and Illustrated Catalog"
.
www.cbi.umn.edu
. CBI Hosted Publications. 1948. Image:
Harvard.Vol 16.1948.subsiderary sequence mechanism
, description:
H Chapter
, pp. 577-578
. Retrieved
May 8,
2018
.
- ^
A Manual of Operation (1946)
:
subsidiary sequence control
, pp. 22, 50, 57, 73, 91
- ^
Wexelblat, Richard L. (Ed.) (1981).
History of Programming Languages
, p. 20. New York: Academic Press.
ISBN
0-12-745040-8
- ^
Williams, Kathleen (November 10, 2012).
Grace Hopper: Admiral of the Cyber Sea
. Naval Institute Press. pp. 33?34.
ISBN
9781612512655
. Retrieved
August 7,
2019
.
- ^
"Columbia University Computing History: L.J. Comrie"
. Retrieved
December 15,
2013
.
- ^
"The Columbia Difference Tabulator - 1931"
. Retrieved
December 15,
2013
.
- ^
a
b
Cohen (2000)
, p. 166
- ^
"Atomic Heritage Foundation: John von Neumann"
. Retrieved
May 12,
2019
.
- ^
a
b
Emerson W. Pugh (1995).
Building IBM: Shaping an Industry and Its Technology
. MIT Press.
ISBN
978-0-262-16147-3
.
- ^
Martin Campbell-Kelly
; William Aspray (1996).
Computer: A History of the Information Machine
.
Basic Books
. p. 74.
ISBN
0-465-02989-2
.
- ^
Powell, Alvin.
"Mark 1, rebooted"
.
Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS)
. Cambridge, Massachusetts: President and Fellows of Harvard College
. Retrieved
July 28,
2021
.
- ^
"Collection of Historical Scientific Instruments Mark I"
.
Atlas Obscura
. Retrieved
May 24,
2016
.
- Publications
- Cohen, Bernard, ed. (1999).
Makin' Numbers
. Cambridge, Massachusetts: The MIT Press.
ISBN
0-262-03263-5
.
- Cohen, Bernard (2000).
Howard Aiken, Portrait of a computer pioneer
. Cambridge, Massachusetts: The MIT Press.
ISBN
978-0-2625317-9-5
.
- Campbell, Robert
(1999),
Aiken's First Machine
in
Cohen (1999)
, pp. 31?63
- Harvard Computation Laboratory (1946).
"A Manual of Operation for the Automatic Sequence Controlled Calculator"
(PDF)
.
In: The Annals of the Computation Laboratory of Harvard University: Volume I
. Cambridge, Massachusetts: Harvard University Press.
Further reading
[
edit
]
- Copeland, Jack
(2006), "Machine against Machine", in
Copeland, B. Jack
(ed.),
Colossus: The Secrets of Bletchley Park's Codebreaking Computers
, Oxford: Oxford University Press, pp. 64?77,
ISBN
978-0-19-284055-4
- Cruz, Frank da (1991).
"The IBM Automatic Sequence Controlled Calculator"
. In Grosch, Herbert R. J. (ed.).
Computer: Bit Slices From a Life
. Third Millennium Books.
ISBN
0-88733-085-1
– via Columbia University Computing History (August 2004).
- Popular Science (October 1944).
"Robot Mathematician Knows All the Answers"
.
Popular Science
. pp. 86ff.
- Zuse, Konrad (1993).
The Computer: My life
. Berlin: Pringler-Verlag.
ISBN
0-387-56453-5
.
External links
[
edit
]
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